Method of constructing horizontal cylindrical tanks



J1me 1942- w. A. SANDBERG I METHOD OF CONSTRUCTING HORIZONTALCYLINDRICAL TANKS Filed March 19, mm

2 Sheets-Sheet l WILLIAM A. SANDBERG //v VEN TOR TORNEY Juize 23, 1942.w. A. SANDBERG 2,287,198

' METHOD OF CONSTRUCTING HORIZONTAL CYLINDRICAL TANKS p V p INVENTORM00; M.

\\ A TTORNEK Patented June 23, 1942 William A. Sandberg, Los Angeles,Calif., as-

signor-to Lacy Manufacturing Company, Los

Angeles, Calif., a corporation of California Application March 19, 1940,Serial No. 324,838

4 Claims. The invention relates to methods for constructing largecylindrical tanks in ahorizontal position.

Tanks of this form, for the storage of light liquids or of compressedgases; have now at- 5 temporaryrollers during the assembling of thetained great dimensions, as for example a diamshell; eter of thirty-twofeet and a length of over two Fig. 5 is an end elevation on a reducedscal hundred feet, and the demand is for even larger of a fabricatedring showing a preferred method tanks. Because of their size, whichrenders it of temporarily staying it against deformation; impossible tomove them any great distance, Figs. 6, 7, and 8 are elevations of aportion these containers must be constructed in the field, one-hal f theank in va i us Stages of in the open air, and the methods conventionallysembling, and used in the shop for assembling of smaller cyl- Fig. 9 isan elevation of the entire tank at the inders either fail completely orbecome unduly stage at which the halves 'may be j i by the costly whenapplied under field conditions, 5 insertion of a single ring. p Tanks ofthis type are customarily made up Referring first to Figs. 1 and'2, thetank may of a plurality of rings joined end to end, the beconsidered asconsisting of aplurality of ring longitudinal seams being staggeredaround the shaped sections |n |u- |n, aclosure in circumference and theheads being hemispheritwo girder rings l2-|2 and the two heads cal orotherwise outwardly. curved. They may I3l3.- be constructed with all theseams riveted, or a hs d rin is provided W th a ir r" M. with thelongitudinal seams riveted and the shown as being placed outside thetank though roundabout seams welded, or with all the seams it y qu lly Wll be p d i The girder welded, as may be preferred, all of thesealterrings a o P d W h Pa of brackets natives being found in priorpractice. It is also I 5 wh h. wh n he nk is pl rest on Well known orotate the t k at intervals, durexpansion rollers and enclosing boxes I6 seated ing construction, to bring portions being worked on onc or o rPiers "I on into convenient locations, particularly to The first step int e Construction o the tank bring seams to be welded into an approximat1 is to erect on each of the foundations a girder horizontal position,ring I2 in or on which the girder has already Briefly stated, the methodconsists in first been perman n ly fix in p i ie ring the erecting oneach of the permanent foundations n t u t p d these rings st on temp aring-shaped section of the tank provided with a y l rs I8 su p rt f thetin s as a strong and rigid girder; in guying o br ing shown in Fig. 3.These rollers are so placed and these girder sections to prevent theirbeing over proportioned that the k which is to be turned by a relativelysmall unbalanced weight; structed on them will be in its final positionwhen in adding material (as prefabricated rings or inc mp AS Shown in Fithe r k l5 dividual sheets) on each side of each erected and expansionrollers av no ye bee section in such m nn as t avoid t great an placedat this stage. The rings are maintained overturning moment due tounbalanced weight, in an upright position by-suitable means, shown untilthe assembled portions of the shell ap- 4 guys though struts may be u 1pre erre preach. to the at which the gap may be The next step is to addmaterial on each side closed by the insertion of a single section or ofi the sheets of which it is composed of each girder ring n such manneras to avo d wh an unbalanced condition exceeding the restrainerevergirder .is referred to herein, ref- I in g capacity of the guying meansprovided. erenceismade to a circumferential girder, which This additionof material may be m the form may be inside h the shellof complete ringsor of single plates, or both.

The h is 9'pl'lleiible t0 the Where complete rings are. added, whichwill of tanks iestins on one, two, or a greater number 0 be possibleuntil the assembly projects at least of foundations, but'as the use oftwo foundations tw or three rings beyond the foundation, the I isordinarily the best practice the method is so rings are fabricated onthe ground and are illustrated in the attached drawings, in which:stayed or braced temporarily to permit them to Fig. 1 is a sideelevation of the tank as cornbe lifted into position and bolted to theshell pleted and resting on its permanent foundations; sections alreadyassembled. For this purpose Fig. 2 is a section as on the line 22 ofFig. 1;

Fig. 3 is an endelevation and Fig. 4 a side elevation of one of thegirder rings resting on- I prefer the method of staying described andclaimed in my copending application Serial No.

324,837, filed simultaneously herewith. This method consists briefly inplacing radius rods 20 in tension between a centrally disposed disc orhub 2| and the inner face of the ring. These rods may be welded at theirinner ends to the hub and also welded at their outer ends to the wall ofthe ring, or the rods may be passed through holes drilled in the ringand tightened and building them in place by adding a sheet ata time tothe part of the shell already assembled will depend on the momentaryrelation between the projected length of the assembly and the strengthof the guying or other restraining means.

l9. Assuming that the girder i4 is stiff enough to resist localdeformation and maintain the girder ring truly circular, the projectedportion of the uncompleted shell is a true cantilever beam and has notendency to deform at its outer end. This, however, is true only as longas the plane of the girder ring is the sole plane of support. If anyattempt is made to resist overturning force by supports placed under theprojecting end, as

for exampleby means of blocking, the outer end of the shell will bedeformed and it will be impossible to continue the'assembling. For thisreason,

in following the method herein described, the guying means i9,'ofwhatever nature, is the sole means for resisting the tendency of themomentarily'heavier end of the shell to subside, and as the distancefrom the girder ring increases, this force correspondingly increases forany given increment of weight. Consequently, while it may be cheaper andmore convenient to prefabricate the rings on the ground and add them asunits, it is seldom or never possible to continue doing so for theentire length of the assembly, and at some point along this length(which will be determined solely by the judgment of the constructor) itwill be necessary to fabricate the rings in place by adding one sheet ata time.

Whichever method of additionis followed, the unbalanced weight due tothe addition of a ringor a sheet is immediately compensated by theaddition to the opposite side of a corresponding element. This isillustrated in Figs. 6 to 9, inclusive. In Fig. 6 a first ring ill-llhas been bolted on the right hand of the girder ring 12; in Fig. '7 asecond ring 1 2 has been added ,on the left hand, thus restoring theweight balance; in Fig. 8 three rings on each side of the girder ringhave been completed and rings ll-I and "-8 have been startedby theaddition of one sheet at each end of the assembly.

In Fig. 9 the shell is shown in the last stage of incompletion; the twohalves (which may have beenconstructed simultaneously or successively)having approached each other until the gap can -be spanned by a singleclosure ring II. The

numbering of the rings on each half of the tank shows the two orderswhich may have been followed in adding rings or sheets. It will be notedthat on the left half the order is right-left-leftright while on theright half the order is rightleft-right-left. The first order is usuallymore convenient. but otherwise they are strictly equivalent, theunbalance due to the addition of a single unit on one side beingcorrected by the following addition of a similar unit on the other '5side of the plane of support.

As soon as the closure ring H has been bolted into place. the guyingmeans ISmay be removed. The heads l3 are then placed and the assemblingof the tank is completed. It may then be rotated 10 on the rollers It,as by means of a roundabout cable and a winch, for convenience in theensuing operations of riveting and/or welding. The tank having thus beenmade tight is tested and, finally, the expansion rollers and boxes iiare placed on the piers, the brackets l5 are positioned on the boxes andattached to the girders, and the temporary rollers H! are thenwithdrawn, allowing the weight of the tank to rest on the brackets. Thetemporary rollers may be removed without lifting the tank if they areinitially placed on wedges which may be driven out after completion ofthe job.

In case it is not desired to rotate the tank during the constructionperiod, as for example if it is to be constructed by the additionofsingle sheets to the girder ring and the welding of each seam as thesheet is placed, the use of the temporary rollers may be omitted. Insuch case the brackets l5 are attached to the girder ring when it isfirst erected, and the expansion rolls and enclosing boxes ii are placedbetween the brackets and the foundations at that time, thus bringing thegirder ring into its final position at the time of erection.

If the completed tank is to be used for the storage of liquids,thegirders which would be required to prevent deformation in use will besufficiently strong and stiff to maintain the shell cylindrical duringthe assembling operation. It'should be noted, however, that if the tankis to be used for 40 the storage of gas under pressure, the girderscalculated for the stresses existing in the use of the tank may beconsiderably too light to maintain the cylindrical form during assembly,and in calculating their section the stresses existing duringconstruction should also be considered.

In the attached claims, the word foundation" is used in the singular todefine the ultimate support for the tank in any one plane normal to thelongitudinal axis, this ordinarily consisting of two piers which may ormay not rest on a common footing.

I claim as my invention:

1. In the construction of horizontal cylindrical tanks: the step ofprojecting a self-supporting 5- cylinder from opposite sides of agirder-stiffened ring section resting in an erect position on afoundation, by successive additions of tank-shell material to oppositesides of said erect section,

the total weight of said section and said added" m material beingtransmitted through said-girder to said. foundation.

2. In the construction of horizontal. cylindrical tanks: the step ofprojecting a self-supporting cylindrical shell from opposite sides of aring section stiffened by a circumferential girder and resting in anerectposition on a foundation, by successive additions of prefabricatedrings of tank-shell material to opposite sides. of said erect section,said additions being made alternately on the two sides of said section,the total weight of said section and said added rings being transmittedthrough said girder tosaid foundation.

3. In the construction of a horizontal cylindrical tank, the stepscomprising: erecting in an axially horizontal position a ring-shapedsection drical tank, the stepscomprising: erecting in an 10 axiallyhorizontal position a ring-shaped section of said tank including astifl' circumferential. girder; bracing said girder to resist anoverturning force; attaching prefabricated rings of tank shell materialalternately at each end. of said section and thus forming a cylinder ofprogressively increasing length, and supporting said cylinder duringsaid construction solely on a foundation bearing only against saidgirder-including section.

' WILLIAM A. SANDBERG.

